This invention relates to a touch responsive control in an electronic musical instrument and, more particularly, to an electronic musical instrument which, in generating in a different tone generation manner, a tone corresponding to a key in a single key area consisting of the whole keyboard or a key in one of plural key areas established by splitting the keyboard, is capable of switching a key area split mode in response to a switching operation and, more particularly, to employment of a key touch detection device common to a plurality of keys.
There is known, for example in Japanese Utility Model Publication No. 313/1981, an electronic musical instrument in which a common touch sensor is provided under a plurality of keys arranged in a single line and a tone is controlled by an output of the touch sensor produced by depression of one of the keys. On the other hand, there has been developed and manufactured an electronic musical instrument in which, as disclosed in U.S. Pat. Nos. 4,365,532, 4,450,745 and 4,351,214, a key area split mode can be switched in such a manner that either a single keyboard is divided in two key areas with a higher-pitch key area being used for playing melody and a lower-pitch key area for playing accompaniment or the entire keyboard is used for playing melody.
A problem in this type of electronic musical instrument is that, if the touch response control is performed with the above described touch sensor which is common to all keys, an effective touch detection output cannot be obtained during the key split mode with a result that a proper touch response control cannot be performed.
It is therefore an object of the present invention to provide, in an electronic musical instrument in which the key area split mode is switched by the switching operation, a touch response device capable of effectively utilizing a key touch detection signal for the tone control in accordance with the key area split mode then available.